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board/modules/Sensors_can/ch32-sensor/README.md

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+
+# ch32v203-bms
+
+A simple battery management controller software.
+
+## CAN bus and hardware address
+
+This firmware exposes a CAN interface on the CH32V203 and uses 4 hardware address pins to allow up to 16 sensors on the same bus.
+
+- CAN pins (default mapping):
+  - CAN RX: PA11
+  - CAN TX: PA12
+- Address select pins (with internal pull-ups):
+  - A0: PA0
+  - A1: PA1
+  - A2: PA2
+  - A3: PA3
+
+Wire each address pin to GND to set its corresponding bit to 1. The 4-bit address range is 0..15. The node’s CAN Standard ID is `0x100 | addr`, i.e. 0x100..0x10F. The CAN acceptance filter is configured to only accept frames with the node’s own ID.
+
+Adjust the pins above if your PCB routes CAN or address lines to different pads.
+
+## 555 timer (software) emulation mode
+
+To save the BOM cost of a classic NE555 in simple oscillator applications, this firmware implements a minimal 555-like Schmitt trigger using the MCU’s ADC and a GPIO, approximating the behavior when the capacitor is charged/discharged via Q through a resistor, and the combined Trigger/Threshold senses the capacitor node.
+
+- Pins used:
+  - Q output: PB2
+  - Combined Trigger/Threshold (ADC input): PA0
+- Wiring:
+  - PB2 (Q) -> series resistor R -> capacitor node
+  - Capacitor node -> capacitor to GND
+  - Capacitor node -> PA0 (ADC input)
+- Behavior:
+  - When ADC(PA0) <= ~1/3 Vref, PB2 is driven High.
+  - When ADC(PA0) >= ~2/3 Vref, PB2 is driven Low.
+  - Hysteresis avoids chatter; the actual charge/discharge dynamics follow your chosen R and C.
+- Notes:
+  - Use an appropriate resistor from PB2 to the capacitor to set oscillation frequency. Start with 10k..100k and adjust with C.
+  - Ensure PA0 is routed to the capacitor node and left high impedance (no strong pull-ups/downs) so the ADC can sense the analog voltage.
+  - PB2 drives the on-board LED (if present), so the LED might blink at the oscillation frequency.
+
+This mode is implemented in `src/main.rs` using `hal::adc::Adc::convert(&mut pin, SampleTime::...)` to take periodic samples and a simple state machine to toggle the Q output based on ~1/3 and ~2/3 Vref thresholds.
+
+## Building
+
+``` sh
+cargo build --release
+```
+
+## Flash
+
+``` sh
+wchisp config reset
+wchip wchisp flash target/riscv32imc-unknown-none-elf/release/bms
+```
+
+## Debugging
+
+For debugging purposes a container file is provided together with wrapper scripts to start the containerized `openocd` and `riscv-gdb` transparently. The wrapper scripts assume that `podman` is setup.
+
+Starting Debug server 
+
+```
+./bin/openocd
+```
+
+Connecting with gdb for interactive debugging
+
+```
+./bin/gdb -f target/riscv32imc-unknown-none-elf/release/bms
+```